Large flatworm/nudibranch hitchhiker?

[toddb]

Found this guy on the glass of my aquarium tonight -- it was eating a dwarf cerith snail. Maybe about 2" long and 1" wide. My tank is about 6 months old with live rock from Florida. Once I turned on the lights in the room it pretty quickly crawled back into the rock. Any idea what this thing is?

Thanks!

 

[toddb]

Here's its underside with the snail it ran off with (black dot).

 

[RedFrog211]

Definitely a nidibranch, not sure specific ID. It might predate on corals- I’ve never seen one that big!

 

[KJ]

Found this guy on the glass of my aquarium tonight -- it was eating a dwarf cerith snail. Maybe about 2" long and 1" wide. My tank is about 6 months old with live rock from Florida. Once I turned on the lights in the room it pretty quickly crawled back into the rock. Any idea what this thing is?

Thanks!

Polyclad flatworm. Remove them!

 

[ReefBridge]

That’s a shame. It’s kinda cool looking, but definitely can’t stay in the DT. It would be cool to set up a small species specific tank for it. And, unlike most nudibranchs, you already know it’s diet!!!